Measuring gauge and method for determining the diameter or cross-sectional area of an object whose cross-sectional shape is adjustable

ABSTRACT

The invention relates to a measuring gauge and a method for determining the diameter or cross-sectional area of an object whose cross-sectional shape is adjustable such as, for example, a litz conductor. A first measuring disc comprising a helical slot running around the center of the measurement disc and tapering down is connected in a rotatable fashion by a central axial connection to a second measurement disc comprising a slot running steadily from the vicinity of the center to the edge, the slot tapering in the same direction as the slot of the first measuring disc. A material measure for reading the detected measurement is provided on one of the two measurement discs. When the measurement discs are counter-rotated to one another, the overlapping sections of the slots form an opening into which the object to be measured is inserted, and the size of the opening is altered by counter-rotating the measurement discs to one another. The diameter or the cross-sectional surface of the remaining opening may be read from the material measure.

FIELD OF THE INVENTION

The invention relates to a measuring gauge and a method for determiningthe diameter or cross-sectional area of an object whose cross-sectionalshape is adjustable such as, for example, a litz conductor.

BACKGROUND OF THE INVENTION

A litz conductor is an electrical conductor that consists of thinindividual wires and is therefore easy to bend. The up to severalhundred individual wires of the litz are mostly enclosed in a commoninsulating sheath.

Litz conductors are primarily used where frequent movements or shakingloads occur—for example, machines, motor vehicles and aircraft androbots—or where a mobile device must be provided, as for exampleelectrical hand tools, network connections capable of being plugged in,or microphone and speaker cables. Depending on the requisite flexibilityand degree of loading, litz conductors are used with thin or ultra-thinwires.

In particular applications, the conductors are packaged, that is,provided with multi-core cable ends, cable shoes, plug connections orthe like.

This packaging is customarily undertaken using so-called crimping. Withthis, a force-locked, homogeneous, undetachable connection is madebetween the conductor and the connecting element, which ensures a highlevel of electrical and mechanical safety. Generally, where it is noteasy to lay a pre-packaged cable, the cable alone is laid to the targetlocation, and only there is an electrical contact piece attached, mostlyby crimping, to the end of the lead. With the aid of crimping pliers,the plug and cable are connected in a force-locked fashion, mostly witha first crimping connection generated in the insulated area and a secondcrimping connection at the insulated end of the cable to produce theelectrical connection.

Along with connection safety, crimping also achieves considerablesimplification in handling. The connection is produced by pressure, withtuned crimp profiles causing a precisely preset deformation of theconnecting element and lead precisely at the connecting piece and leadcross section.

If cables are packaged only after being laid, i.e., provided with therequisite connections, then, especially in large wire harnesses withmany different line cross sections, the result can be that on-sitetechnical personnel may not be able to choose suitable crimping profilesfor the particular cables or litzes, especially because, with thesmaller lead cross sections, it simply may not be possible to scrutinizethe result to assess the lead cross section.

The results are either electrical and/or mechanical connections that aretoo loose and get become detached on their own, or incomplete crimpconnections, in which a part of the litz conductor not connected inform-locked fashion with the contact untangles, which under certaincircumstances may lead to short circuits in the wire harness.

Using, for example, a vernier to measure the diameter of the leadproduces erroneous readings due to the mobility of the litz conductor;the individual wires are pushed against each other and compressed flatby the legs of the vernier, so that it is not possible to preciselydetermine the cross-sectional area.

Measurement of the diameter of the lead with insulation would bepossible, but cannot necessarily be inferred from the lead crosssection, because insulation may have varied thicknesses with differenttypes of leads.

U.S. Pat. No. 2,374,830 A discloses a measuring gauge for determiningthe thickness of knitting needles and other objects having a circularcross section. The measuring gauge consists of a housing with a taperedspigot slot through which the object can be run. The display comprises ascale and a display element which is pressed using a spring against theobject to be measured, to allow a readout of the diameter on the scale.

JP 04-118501A represents a solution for checking the cross-sectionalform of an object. The measuring instrument consists of an upper andlower measuring strip, between which the measured object is placed, withmeasurement conducted by two interlocking contact surfaces in the tool.

SUMMARY OF THE INVENTION

The task that is the basis of the invention is to provide a device fordetermining the diameter and/or the cross-sectional area of an objectwhose cross-sectional form is altered when force is applied.Specifically, simple and precise determination of the lead cross sectionof litzes should be made possible.

According to the invention, the problem is solved by a measuring gaugewith the features of claim 1 or of claim 15, and by a process with thefeatures of claim 14.

The advantages of the invention are especially to be seen in that theinstaller can easily and quickly do an on-site determination of theactual lead cross section, avoiding incorrect packaging of the lead andthus also avoiding technical breakdowns.

According to the invention, a measuring gauge comprises at least a firstmeasuring disk and a second measuring disk. The first measuring disk hasa slot which has a spiral shape. The spiral tapers in width along itscourse, either from the interior outwards or from the outer part towardthe interior. The second measuring disk also has a slot on which thereis a taper in the same direction as with the slot in the first disk. Theslot of the second measuring disk has a constant course, going from thevicinity of the center of the measuring disk outwards. The slot of thesecond measuring disk can be designed as a straight line or also as aspiral.

The width of the slots in the measuring disks ranges at least from thelargest possible diameter of a cross-sectional area to be determined tothe smallest diameter to be measured.

The measuring disks are placed coaxially one above the other in such away that the slots overlap to make a residual opening. If the measuringdisks are counter-rotated to one another, the size in the clear and alsothe position of the opening are changed.

Preferably the slot of the second measuring disk is congruent to that ofthe first measuring disk, and the measuring disks are placed in specularsymmetry, thus resulting in an essentially rhombus-shaped opening in theoverlap area.

In an especially preferred embodiment of the invention, a thirdmeasuring disk is placed coaxially with the other two measuring disks,which has a radially-running slot, that tapers in the same direction asthe slots of the other two disks. If the first and the second measuringdisk are counter-rotated to one another, then the residual opening inthe area where the slots of all three disks overlap has an essentiallyhexagonal form.

Providing additional measuring disks also is within the scope of theinvention. Preferably they have a spiral shape with a different length.By using additional measuring disks, the residual opening can further beapproximated to a circular shape. True, care then must be taken that thedisks are so rotated relative to each other that a penetrating openingstill remains free. For this possibly an appropriate transmission or adrive must be provided between the separate disks.

For determination of the cross-sectional area or of the diameter of anobject whose cross-sectional form can be altered, first the opening isset to such a size that the object can be inserted into the opening.Then the measuring disks are counter-rotated to each other until theobject is securely held in the opening. Due to the opening becomingsmaller from all sides, the object to be measured is compressedcentrically, so that the diameter of the object can be determined to agood approximation, from which then the cross-sectional area can becomputed or determined from an appropriate scaling.

The determined dimension, which is the diameter or the particularlypertinent cross-sectional surface, can be read out to a material measurewhich is applied to a measuring disk that lies without, along the slotor on the edge. The material measure becomes more precise, the longerthe slot is, and therefore the material measure preferably is providedon the first measuring disk. The readout occurs on a section of thespiral in which the object protrudes out of the opening, or at a markingwhich lies opposite the material measure placed on the edge.

It has been shown to be particularly advantageous with a preferredembodiment form to provide a drive that permits a uniform relativecounter-rotation of the measuring disks to each other. Depending on thearea in which the measuring gauge is used, this may be a manual drive,with a handwheel for example, or also a mechanical drive with anappropriate gear.

In a very simple embodiment form, holding sections are placed on theouter edge of the measuring disk, which make possible a manualdisplacement of the disks. Preferably here also a drive is to beprovided that controls the relative turning motion of the measuringdisks.

In a preferred embodiment form, the measuring disks are manufactured outof plastic. Other materials such as aluminum or steel are alsoconceivable, however.

As a possible application for the invention, a description follows ofdetermining the lead cross section of a litz conductor, which, accordingto the invention, represents an object whose cross-sectional form can beadjusted. However, the invention is not expressly restricted to thisarea of application. For example, the measuring gauge is also suited fordetermining the diameter of optical waveguides, with damage safelyavoided even in thin conductors.

In still another preferred embodiment form of the invention, themeasuring gauge comprises a material measure for the cross-sectionalarea and an additional material measure on which the diameter can beplotted. This makes possible a very simple determination of the leadcross section and overall diameter of the litz conductor. Since with anequal lead cross section, litz conductors may have insulation of variedthicknesses, different crimp contacts are also required. Measurement oflead cross section and insulation or overall diameter makes it easy tocorrectly choose the crimp contact to be used.

In addition, one of the measuring disks can include an additionalaperture which, for example, is configured with a sharp edge, so thatvia rotation of the measuring disks, the measuring gauge also can beused to cut off or dismantle the litz conductor.

Likewise, it is conceivable to directly integrate the invention-specificmeasuring gauge into crimping pliers, or thus to implement automaticrecognition of the litz conductor in a crimping machine, so that forexample, after insertion of the lead, the requisite crimp contact can bemeasured and then automatically selected.

It is also advantageous, if measuring disks are manually operated, touse the disk area that is available and not being used to affix thematerial measure, as an area for advertisement.

As can be gleaned from the explanations provided before, it is importantfor the invention that two disks are displaced relative to each other,to alter the cross section of an opening which remains in theoverlapping area through two tapering slots running on the measuringdisks. Although it is advantageous to apply two or more disks that arerotatably placed, this principle can also be used with disks to be usedin a linear fashion. An embodiment form to that effect is defined withgreater detail in the appended claim 15.

A preferred embodiment form of the invention is depicted in the figuresand will be explained in more detail in what follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a measuring gauge for determining a lead cross section in athree-dimensional view.

FIG. 2 shows the measuring gauge according to FIG. 1 in across-sectional view.

FIG. 3 shows a first measuring disk of the measuring gauge in a top viewand in a side view.

FIG. 4 shows a third measuring disk with a radially running slot in atop view and cross-sectional view.

FIG. 5 shows a second measuring disk in a top view.

FIG. 6 shows the measuring gauge according to FIG. 1 in a top view witha depiction of a material measure.

DETAILED DESCRIPTION

FIG. 1 is a three-dimensional view of an especially preferred embodimentform of a measuring gauge 01. The measuring gauge 01 depicted here ispreferably suited to determine the lead cross section of a litzconductor, and for that reason in the pertinent description, referenceis made only to this use. One skilled in the art can easily derivefurther application possibilities. FIG. 2 is a cross-sectional depictionin which the individual parts of measuring gauge 01 are more easilyrecognized.

The measuring gauge 01 comprises a first measuring disk 02, a secondmeasuring disk 03 and a third measuring disk 04. Measuring disks 02, 03and 04 are placed concentrically and are able to counter-rotate to eachother, and in the center 05 are connected by an element comprising arivet 06, a push button or the like.

The first and second measuring disks 02, 03 each have a helical slot 07,08 that tapers down toward the outside. The third measuring disk 04 hasa radially running slot 09, not shown here (see FIG. 4), which alsotapers down toward the outside. The edges of slots 07, 08, 09 arepreferably rounded off, so that one or more individual wires of the litzconductor do not get cut off or damaged inadvertently when measuringdisks 02, 03 are rotated. The first and second measuring disks 02, 03are placed in specular symmetry to each other, and third measuring disk04 is in the plane of symmetry between the first and second disk.

Additionally, measuring gauge 01 comprises a manual wheel 11 with apinion 12. Pinion 12 engages into each row of teeth 13, 14 of the firstor second measuring disk 03 or 04, with the rows of teeth 13, 14provided to form a circle on the inner sides facing each other of firstor second measuring disk 02 or 03. If manual wheel 11 is turned, thenthe outer measuring disks 02 and 03 rotate counter to each other,corresponding to the gearing ratio that is determined by the rows ofteeth 13, 14 and the pinion 12 that engages into them.

If differing spiral lengths are provided on the first and secondmeasuring disk, the gearing of the rows of teeth is to be givendifferent dimensions, so that when rotated, the desired opening alwaysremains that is formed by the overlapping slots. For this, separateddrive wheels are provided.

In FIGS. 3 to 5, the individual measuring disks 02, 04 and 03 are shownseparately, and in fact the sequence of the figures corresponds to thesequence of measuring disks 02, 04, 03 that are placed on one another.The sequence of measuring disks shown here derives from structuralreasons, but is not prescribed.

FIG. 3 shows in depiction a) a side view, and in depiction b) the innerside of first measuring disk 02. The row of teeth 13 is provided on theinner side of first measuring disk 02 on the outer edge, and is offsetto a base surface 16. The interval between teeth is adjusted to thedesired gear ratio and the pinion 11. Helical slot 07 runs from a pointP close to the center counterclockwise with diminishing width at anangle α of about 220°. By a possible lengthening, the measured area orthe resolution can be altered.

FIG. 4 shows the third measuring disk 04 in depiction a) as a crosssection and in depiction b) as a top view. In depiction b), theprogression of the radially running slot 09 is perceptible. Slot 09 runsfrom a point Q close to the center outward in a radial direction. Itswidth diminishes during its course. Adjoining the outer side of thethird measuring disk, via an elevated section 17, is a gripping edge 18with multiple recesses 19. At one location along the circumference, anaperture 21 is provided in the radial direction, through which themanual wheel 11 can be inserted when measuring gauge 01 is assembled. Atthe same location on the circumference, the elevated section 17 has anaxial aperture 22 into which the pinion 12 is positioned in a connectionallowing it to act as a drive with manual wheel 11. In addition, ongripping edge 18 a marking 23 is provided, at which the lead crosssection can be read out on second measuring disk 03.

FIG. 5 shows second measuring disk 03 in a top view of the outer side.In this embodiment form it is designed to be identical to firstmeasuring disk 02, and therefore no further explanation is providedhere.

In FIG. 6, the measuring gauge 01 is shown with a material measure 24attached to second measuring disk 03. In this view the remaining opening26 can be seen. The resulting lead cross sections are assigned viamaterial measure 24 to the particular remaining opening cross section26. These can be read out on the marking 23. With a further rotation ofmeasuring disks 02, 03 the remaining opening 26 “migrates” outward, incorrespondence to the radial slot 09 in third measuring disk 04. Thedepicted value of the material measure 24 that is shown opposite marking23 corresponds to the lead cross section of a litz that fits exactlyinto the particular adjusted opening 26. For use as a measuring gauge todetermine the lead cross section, it suffices to apply onto the materialmeasure those lead cross sections actually used in the industry. Theparticular closest value that stands opposite marking 23 is thedetermined cross section of the litz employed, with sufficientprecision.

Also conceivable would be colored or other markings along helical slot07 on first measuring disk 02, which directly represent the lead crosssection or the required crimp contact.

1. A measuring gauge for determining a diameter or a cross-sectionalarea of an object whose cross section can be adjusted, with a firstmeasuring disk, which has a helical slot that runs about the center ofthe measuring disk and which tapers down; a second measuring disk, whichhas a slot running constantly from the area of the center to the edge,which tapers down in the same direction as the slot of the firstmeasuring disk; a material measure for reading out the measuredetermined, which is provided on one of the two measuring disk; with themeasuring disks being placed one atop the other with a central axialconnection and able to counter-rotate relative to each other, with theslots of the measuring disks configured to be applied by sections inoverlap, so that they leave a through-running opening into which theobject to be measured can be inserted, and through counterrotation ofthe measuring disks relative to each other, the width of the opening canbe altered, and on the material measure the diameter and/or thecross-sectional area of the particular remaining opening can be readout.
 2. The measuring gauge of claim 1, wherein the second measuringdisk likewise has a helical slot, with the helical slots having adiffering length, with the measuring disks so placed that the helicalslots run counter to each other, and such that the opening has anessentially rectangular shape.
 3. The measuring gauge of claim 1,wherein the first and the second measuring disk have a congruent helicalslot, with them being placed in specular symmetry to each other, throughwhich the opening essentially has a rectangular form.
 4. The measuringgauge of claim 3, further comprising a third measuring disk that has aradially-running slot, which tapers down in the same direction as theslots of the first and second measuring disks, with the opening havingan essentially hexagonal shape when the first and second measuring disksare counter-rotated to each other.
 5. The measuring gauge of claim 1,wherein the material measure is provided on the first measuring disk. 6.The measuring gauge of claim 1, wherein the slot of the first measuringdisk extends at maximum over one revolution (360°) of the disk.
 7. Themeasuring gauge of claim 6, wherein the slot of the first measuring diskextends over an angle α=220°.
 8. The measuring gauge of claim 1, furthercomprising at least one additional measuring disk with a helical slot,with the remaining opening having a polygonal cross section.
 9. Themeasuring gauge of claim 1, wherein the width of the slots in themeasuring disks constantly tapers down from the largest object crosssection to be measured to the smallest object cross section to bemeasured.
 10. The measuring gauge of claim 1, wherein the measuringdisks include holding sections which are located on an outer edge of themeasuring disks.
 11. The measuring gauge of claim 1, further comprisinga drive and a transmission unit for rotation of the measuring disks. 12.The measuring gauge of claim 11, wherein the drive is a manual wheel andthe transmission unit includes a drive pinion which is attached onto themanual wheel so as to act as a drive, and engages into a row of teethwhich is placed in circular fashion on the inward-facing side of thefirst or second measuring disk.
 13. The measuring gauge of claim 1,wherein one of the measuring disks has formed therein an additionalaperture which has a sharp edge, so that when the measuring disks arerotated, the object inserted into the additional aperture is subject toa shearing action.
 14. A procedure for measurement of a cross-sectionalsurface of an object whose cross section can be altered, comprising:concentrically placing at least two measuring disks with a firstmeasuring disk having a tapering helical slot and a second measuringdisk, that lies opposite and parallel to the first measuring disk,having a steadily running slot that tapers down in the same direction,and overlapping sections of the slots of the measuring disks leavingopen a through-running opening; inserting an object to be measured intothe opening; counter-rotating the measuring disks relative to each otheruntil the opening has become small enough that the measured object issecurely clamped in the opening; reading out the cross-sectional area orthe diameter on a material measure attached to one of the measuringdisks.
 15. A measuring gauge for determining a diameter or across-sectional area of an object whose cross section can be adjusted,with a first measuring disk which has a linear slot that runs in a firstdirection and which tapers down; a second measuring disk which has alinear slot running in a second direction and which tapers down; amaterial measure for reading out the measure determined which isprovided on one of the two measuring disks; with the two measuring disksbeing placed one atop the other and configured to be adjusted againsteach other, with the slots of the measuring disks able to be applied bysections in overlap, so that they leave a through-running opening intowhich the object to be measured can be inserted, and through adjustmentof the measuring disks relative to each other, the width of the openingcan be altered, and on the material measure the diameter and/or thecross-sectional area of the particular remaining opening can be readout.